London’s St. Martin-in-the-Fields church was home to the graves of plenty of English noblemen, but it had never seen a pair of graves quite like this. They belonged to Kamehameha II and his queen, Kamamalu, and they were just temporary resting places. It was July 1824, and soon, the Hawaiian king and queen would be disinterred and put on a ship back to their home, the Sandwich Islands.

Just days before, the royals’ every move had been avidly covered by the press, from Kamamalu’s provocative enjoyment of cigars to Kamehameha’s trip to the city’s zoo and puppet theater. The interest was well warranted: The Hawaiian king and queen may have been looked down upon by George IV’s court, but they were also London’s most talked-about couple.

Now, though, they were dead, the victims of measles they are thought to have contracted during a visit to the Royal Military Asylum, an orphanage for the children of military parents that was known for its epidemics of childhood diseases.

The measles deaths of Hawaii’s monarchs were tragic—and foretold another tragedy. When measles finally hit the Hawaiian islands in 1848, it began a long sequence of epidemics that tore the kingdom apart. Until their contact with Europeans, Hawaiians had lived in isolation which helped their culture and population flourish. That isolation ended up contributing to their downfall. During the 19th and early 20th century, epidemics of measles, smallpox and other diseases threatened to wipe out the entire Native Hawaiian population and disrupted the culture and lives of the island’s residents.

By the time Kamehameha II and his queen, Kamamalu, headed to England in 1824, Hawaii had been in contact with Europeans for nearly half a century. In 1778, Captain James Cook explored the islands. He paid the price: After attempting to kidnap Kalaniʻōpuʻu, who ruled over of the island of Hawaii, in retaliation for the theft of one of his boats, Cook was killed by one of the chief’s attendants. After Cook, Hawaiian culture changed. Sporadic contact with Europeans introduced Native Hawaiians to different forms of warfare and government. In 1810, Kamehameha I used European-style warfare to take over and unite all of the Hawaiian islands.

European contact didn’t just change the structure of Hawaii. It also brought new diseases to the islands. Cook’s crew introduced sexually transmitted diseases like syphilis and gonorrhea. Because of their island location, Native Hawaiians lacked immunity to infectious diseases like these, and they spread quickly. So did a “plague” that struck the island around 1803. Thought to have been yellow fever or a similar disease, the epidemic resulted in up to 175,000 deaths, cutting the island’s pre-contact population in half.

Meanwhile, Kamehameha I’s family dynasty flourished. He died in 1819, and his first-born son succeeded him to the throne. Known as impulsive, Kamehameha II was fascinated by the foreign missionaries who had begun to come to the islands. In 1823, against his court’s advice, he sailed for England with his favorite of his five wives, Kamamalu, with the goal of thanking George IV, who had sent him a ship.

The visit was unannounced, and the monarch’s arrival in London was the talk of the town. The appearance and behavior of the unfamiliar couple fascinated English observers, who reported on their every movement. Though the public was enthralled by the visitors, George IV put off seeing them. “As if I would sit at the table with such a pair of damned cannibals,” he said.

That biased perception of Hawaiian islanders was common among the British, who looked down on Native Hawaiians’ religion and considered them to be uneducated and uncouth. By the time the king finally agreed to meet the Hawaiian delegation, Kamahameha II and Kamamalu were dead.

Though George IV did pledge to guard Hawaii from outside invasion, he could not protect the islands from the epidemics that followed. In 1848, measles and pertussis made their way to the Kingdom of Hawaii via missionaries and ships’ crews, killing off a quarter of the population.

It was just the beginning: wave after wave of infectious disease continued to hit Native Hawaiians. Since Native Hawaiians lacked any exposure to these disease at all, they were even more susceptible to even benign-seeming infections. “An illness that was considered to be relatively mild could cause severe or fatal consequences to the unprotected native population,” write historians Robert C. Schmitt and Eleanor C. Nordyke. Climate, geography, and poor medical treatment exacerbated the outbreaks, they note.

“Hawaiians were an extraordinarily strong and healthy people who lived in a bubble, a kind of bubble that was a paradise in many respects,” historian David Stannard told Honolulu Magazine. “But when that bubble was penetrated by ships laden with people who carried an armada of diseases—diseases that they themselves could live with—it destroyed the Hawaiians who simply had no defenses to diseases like syphilis and tuberculosis, not to mention diseases like mumps and measles that we shrug off as childhood illnesses.” Meanwhile, writes historian R.D.K. Herman, American missionaries wrote off diseases as being the fault of Native Hawaiians’ dress, parenting, religion, or immorality.

Another disease that wreaked havoc among Native Hawaiians was Hansen’s disease. Known as leprosy at the time, it disproportionately affected Native Hawaiians. People with Hansen’s disease were shunned and forced to live in remote leper colonies. Herman notes that public worries about leprosy were used to cast Native Hawaiians and unclean and unhealthy, just as wealthy American interests were trying to cast the Hawaiian monarchy from their country.

These narratives helped white missionaries and plantation owners justify their control of the islands. During the 19th century, they turned Hawaii from a Native stronghold into a missionary-controlled plantation colony. The United States overthrew the Hawaiian monarchy in 1893.

By 1920, there were fewer than 24,000 Native Hawaiians left in Hawaii. Today, Native Hawaiians face significant health disparities compared to their white counterparts. According to the Centers for Disease Control and Prevention, Native Hawaiians have significantly higher rates of sexually transmitted diseases, HIV/AIDS, hepatitis, and tuberculosis.

Despite those challenges, the Native Hawaiian population is on the rise. By 2060, there are projected to be more than 500,000 Native Hawaiians in Hawaii, in part due to higher fertility rates. But those growing numbers can’t undo the devastating effects of the infectious diseases settlers brought to the Hawaiian islands—diseases that changed the very fabric of Native Hawaiian society forever.